The trifluoromethylthio and trifluoromethylsulfonyl groups are important nuclear substituents in the preparation of potential new dyes, medicinal agents, fungicides, insecticides, and solvents. At present, there are two standard procedures for the introduction of a trifluoromethylthio group into an aromatic nucleus. The first method requires a photoinitiated chlorination of an aryl methyl sulfide side chain, followed by reaction with antimony trifluoride (Eq. 1). O. Scherer, Angewante Chem., 52, 457 (1939); French Pat. No. 820,796 (1937). ##EQU1## The second method uses trifluoromethanesulfenyl chloride in either one of two ways. In one procedure (Eq. 2), W. A. Sheppard. J. Org. Chem., 29, (1964) reaction of an aryl Grignard reagent with trfluoromethanesulfenyl chloride gives the desired aryl trifluoromethyl sulfide, while in the other procedure (Eq. 3), S. Andreades et al., J. Org. Chem., 29, 898 (1964), reaction of activated aromatic derivatives, such as anilines, with trifluoromethanesulfenyl chloride leads to para-substituted aryl trifluoromethyl sulfides. When higher temperatures and Lewis acid catalysts are used, less activated aryl derivatives undergo reaction, but mixtures of aryl trifluoromethyl sulfide isomers are obtained. ##STR1##
Alkyl trifluoromethyl sulfides have been prepared from the reaction of bis-(trifluoromethylthio)mercury or trifluoromethylthiosilver with alkyl iodides. Also, trifluoromethylthiosilver has been used to prepare benzyl trifluoromethylsulfides from benzyl iodides.